1. Field of the Invention
The present invention relates to an assist system for complementing the field of view of a driver by providing information on the environment of a vehicle or a dead angle (spot) in the driver""s view by display of a picture on an internal monitor with superimposing of the assisting information, if necessary, for the driving operation.
2. Description of the Related Art
An automobile has a body which entirely surrounds the driver so that the driver cannot be free from a dead spot in his field of view which is shielded by the portions of the automobile body other than the windows. This dead spot or dead angle should be eliminated for avoiding a low obstacle on a narrow road or a moving obstacle. In order to indirectly acquire information on such dead spot, therefore, the vehicle has been equipped in the related art with dead angle eliminating means, as represented by an under-mirror of a large-sized vehicle. In view of the higher performance and the smaller size of display units in recent years, there have been proposed a variety of devices utilizing the display unit. Of these proposals, an especially wide dead angle range is effectively covered by the technique which has been disclosed in Japanese Patent Laid-Open No. 142210/1997. This related art includes an image pickup unit for taking an image of the environment, and a monitor for displaying the picture taken by the image pickup unit. The image pickup is mounted on the upper central portion of the back of the vehicle as to provide a view from the region just behind the vehicle to the region horizontally outward from the vehicle on one screen. In the picture taken in this case, a portion (e.g., bumper) of the rear end portion of the vehicle is positioned at a lower portion of the screen, and infinity (or a horizontal line) is shown at an upper portion of the screen.
According to the aforementioned method of the related art in which the image pickup unit is disposed generally at the center of the vehicle, however, the image pickup unit cannot be positioned as high in a vehicle having a small height such as a passenger automobile as in a large-sized vehicle. At a corner of the vehicle, most important for avoiding an obstacle, the angle between a vertical line drawn from the corner outer edge of the bumper to the ground and a straight line joining the image pickup unit at an upper portion of the center of the vehicle and the corner outer edge of the bumper becomes so large that the picture thus obtained has the obstacle superimposed over a background of the corner of the bumper. This makes it difficult to sense the distance between the vehicle corner and the obstacle. Further, because of the large angle, a dead angle is left in the vicinity of the bumper corner so that a low obstacle nearby cannot be seen.
In order to reduce the distortion of the picture and thereby provide a proper sense of distance, it is conceivable to provide a combination of the dedicated various drive assisting systems of the related art, for a specific driving operation, to cover the dead angles individually by individual image pickup units arranged at different positions on the vehicle, so that the information from those individual units, as required for the vehicle operations, can be acquired by selecting them properly at the same time or as necessary. Generally, however, the information by the monitor screen is not such that it is easy to grasp at a glance and at a high speed which direction of the vehicle the screen corresponds to or which position it is taken from. When the behavior of the vehicle, i.e., the driving operation, and the change in the picture are independent, the information on the screen cannot be effectively exploited, even if acquired, in difficult driving operations.
Accordingly, the invention has, as its main object, provision of a drive assisting system for acquiring dead angle information, from which the distance can be easily determined, while covering a relatively wide area by displaying a picture providing an unobstructed field of view for the driver.
In order to achieve the above-specified object, according to the invention, there is provided a drive assisting system comprising an image pickup unit disposed on a vehicle for viewing the area in the vicinity of the vehicle, wherein the image pickup unit is oriented longitudinally inclined with respect to a reference position, wherein the upper side of the field of view is directed forward of the vehicle and where the optical axis is directed vertically downward, to obtain an image including at least the edge portion of the vehicle and an area in the front/rear of the vehicle.
In another aspect, the invention provides a drive assisting system comprising an image pickup unit disposed on a vehicle for viewing the area in the vicinity of the vehicle, wherein the image pickup unit is oriented transversely inclined with respect to a reference position, wherein the upper side of the field of view is directed forward of the vehicle and wherein the optical axis is directed vertically downward, to obtain an image including at least the edge portion of the vehicle and an area to the left or right of the vehicle.
According to the invention, moreover, there is provided a driver assist system comprising an image pickup unit disposed on a vehicle for viewing the area in the vicinity, wherein the image pickup unit is oriented longitudinally or transversely inclined with respect to a reference position, where the upper side of the field of view is directed forward of the vehicle and where the optical axis is directed vertically downward, to obtain an image including at least the edge portion of the vehicle, in accordance with the front/back or left/right position on the vehicle.
In order to provide a sense of the image matching the driver""s view, it is advantageous to dispose the image pickup unit with its optical axis directed in substantially the same direction as a vertical plane containing a straight line joining the driver and the image pickup unit. As a result, it is possible to acquire a monitor picture in which the direction in the picture is substantially aligned with the direction of view of the image pickup unit from the driver""s seat.
In order to facilitate a sense of orientation of the two corners of the vehicle and the direction of the vehicle on the picture, it is advantageous that the image be rotated on the optical axis so that the corner of the vehicle in the image properly relates to the corner on the opposite side.
According to the invention, there is also provided a driver assist system comprising an image pickup unit disposed on a vehicle for providing information in the form of images of the environment of the vehicle; a control unit for processing the image taken by the image pickup unit; and a monitor for displaying the image processed by the control unit, wherein the image pickup unit is so disposed over a corner of the vehicle that its optical axis is directed in a direction to view the corner of the vehicle, the environment at least in the vicinity of the corner and infinity on one display screen.
It is advantageous that the infinity is displayed across the entire transverse width of the monitor screen. Because infinity is displayed across the entire transverse width of the monitor, the field of view in the picture is made to resemble the actual field of view from the driver""s seat.
To make the taken picture resemble the driver""s field of view, it is advantageous that the infinity contains the front face of the vehicle; and that the front face infinity is displayed over the corner of the vehicle on the monitor. Because the displayed infinity contains the front face of the vehicle, the direction of the vehicle at each instant can be more easily understood, along with its positional relationship.
It is also advantageous that the left and right images be inclined transversely opposite on the optical axes. Because the taken picture is displayed without any special processing on the monitor, the image of the corner of the vehicle can be displayed at the corresponding corner of the monitor screen so that the left/right sides of the vehicle can be easily differentiated.
To make the images resemble the driver""s actual field of view, moreover, it is advantageous that the image pickup unit is disposed at a position where the front face infinity of the vehicle is horizontal in the display on the monitor. Because the front face of the vehicle is shown horizontal at infinity in the display on the monitor, the similarity between the actual field of view from the driver""s seat and the field of view in the monitor display is enhanced.
In order to assist various driving operations, it is advantageous that the image pickup units be disposed at the two left and two right corners of the vehicle, so as to eliminate the dead angles (spots) at the left/right corners of the vehicle.
When transverse symmetry is necessary for the taken picture, it is advantageous that the image pickup unit at one of the left and right corners of the vehicle, be disposed with its optical axis directed in substantially the same direction as that of a vertical plane containing a straight line joining the driver and the image pickup unit, whereas the image pickup unit at the other left/right corner is disposed at a position symmetric therewith relative to the longitudinal center axis of the vehicle.
To provide a further drive assist, the control unit may include predicted locus synthesizing means for superimposing a movement predicted locus, extending from the corner of the outermost edge of the vehicle according to a steering angle, over the picture display on the monitor. As a result, it is possible to predict on the monitor display whether or not the obstacle can be avoided. Therefore, it is possible to perform a smooth operation without the switchbacks frequently required for obstacle avoidance with such assist. The predicted locus is synthesized according to whether the range selected in the transmission of the vehicle is forward or reverse.
In order that the assist information correspond to the driving operation and the road situations, the control unit may advantageously include display picture switching means for automatically switching the display screen by deciding forward or reverse based on the selected range and by deciding necessity based on at least one of the steering angle and road information obtained from a navigation system. As a result, it is possible for the driver to acquire the assisting information without imposition of any operational load on the driver.
In the interest of safety, it is advantageous that the control unit includes display picture selecting means for automatically displaying the pictures taken by the image pickup units, disposed at the two vehicle corners having a tendency to approach an obstacle, on the monitor within a range where the distance of the obstacle to the vehicle is no more than a predetermined value.
In the interest of preventing confusion from the assist information, it is effective that the control unit includes release means for releasing the automatic display switching of the screen when the answer of the necessity decision is NO.
In order to facilitate a sense of distance by reducing distortion of the picture, it is advantageous that the control unit includes criterion distance synthesizing means for superimposing a criterion distance line, indicating spatial distance from the two vehicle corners on the monitor display in accordance with the picture displayed on the monitor.
In order to make the picture more observable, it is advantageous that the control unit includes contour synthesizing means for superimposing the contour of the vehicle on the monitor in accordance with the picture displayed on the monitor. As a result, even when the contrast or brightness of the monitor screen is reduced by an insufficiency of light or reflection of light, according to the weather conditions, so that the discrimination between the vehicle and its surroundings becomes difficult, the boundary between the vehicle and its surroundings can be made more clear by synthesizing the contour lines to make the two contours of the vehicle observable on the screen.
To compensate for the loss of information due to the focusing (selection) of the assist information, it is advantageous that the control unit includes warning means for notifying the driver of auxiliary information which is not contained in the information of the picture displayed on the monitor. Such notification of loss of information caused by focusing the assist information may be made automatically.
Depending upon whether the image pickup unit is disposed on the front or rear of the vehicle, the direction of the view relative to the vehicle is inverted upside-down in the taken picture, so that the picture conforming to the actual longitudinal field of view can be taken by displaying the taken picture of the image pickup unit as is without any special processing.
In accordance with whether the image pickup unit is disposed on the left side or the right side of the vehicle, the direction of the view relative to the vehicle conforms to the actual transverse field of view with display of the taken picture as is without any special processing on the monitor.
The image pickup units disposed on the front/rear sides or on the left/right sides of the vehicle, provide a view looking in a direction relative to the vehicle which is inverted upside-down in the longitudinal direction and which conforms to viewing in the transverse direction in the taken picture, so that a picture conforming to the actual longitudinal/transverse field of view can be presented as is, without any special processing on the monitor.
By disposing the image pickup unit at a position where its optical axis is directed in substantially the same direction as that of a vertical plane containing a straight line joining the driver and the image pickup unit, it is possible to provide a picture which corresponds to (is generally aligned with) the gazing direction as viewed from the driver""s seat.
When the taken picture is displayed without any special processing on the monitor, the image of the corner of the vehicle can be displayed at the proper corner of the screen so that distinction between the left and right sides of the vehicle can be facilitated in viewing of the displayed picture.
The image pickup unit is disposed over the corner of the vehicle so that the angle between a vertical line drawn from the outermost edge of the vehicle corner to the ground and a straight line joining the image pickup unit and the outermost edge of the corner of the vehicle is very acute. In all the peripheral situations of the vehicle, it is possible to acquire a picture in which the ground surface is in accordance with the distance between the vehicle corner and an obstacle. This makes it possible to confirm the distance between the obstacle and the vehicle, i.e., its corner. On the other hand, the vehicle corner and its vicinity are displayed, as necessary dead angle information for avoiding collision, on one screen simultaneously with infinity, for effectively communicating the positional relationship at a glance. As a result, the positional relationship on the screen is similar to that in the view of the environment from the driver""s seat.